The present invention relates to coating compositions prepared from Michael adducts.
The formulation of coating compositions using Michael addition products has been detailed in a number of references. U.S. Pat. No. 4,248,753 to Buchwalter et al relates to curable compositions in which the resinous binder is the Michael adduct of a primary and/or secondary amine and a polymeric material containing alpha,beta-ethylenically unsaturated moieties in conjugation with carbonyl moieties. The preferred Michael adducts prepared in accordance with the Buchwalter et al reference also contain active hydrogens which are reactive at elevated temperatures with a curing agent. The Michael adducts of the Buchwalter et al reference, however, are unstable adducts. That is, the Michael adduct decomposes under curing conditions releasing free amine which volatilizes.
U.S. Pat. No. 4,341,676 to Patricca et al relates to resinous compositions which are prepared by reacting an N-methylol ethylenically unsaturated amide with a polymer which contains a mercapto and/or a pendant amino group which is a primary and/or secondary amine, or the mixture of the aforesaid polymers. It is theorized in the reference that the reaction mechanism involved in the preparation of the compositions is that of a Michael addition. The polymer, through the pendant amino or mercapto groups, adds to the N-methylol ethylenically unsaturated amide at the site of unsaturation, thereby forming the compositions of the invention. There is no disclosure in the Patricca et al reference of the use of materials containing more than one alpha,beta-ethylenically unsaturated moiety. The disclosure is solely directed to N-methylol ethylenically unsaturated amides.
U.S. Pat. No. 4,330,640 to Buchwalter relates to amide adduct resinous compositions prepared from polymers having pendant unsaturated groups. The resinous compositions are prepared by aminating the polymers containing the unsaturated groups at the ethylenically unsaturated position, with ammonia or a primary or secondary amine which may be volatile or non-volatile. The Michael adducts of the Buchwalter reference are also unstable under curing conditions. That is, they decompose and the amine is volatilized.
The formulation of coating compositions from Michael addition products which contain hydroxyl functionality, are stable under curing conditions of less than 300.degree. F. (149.degree. C.) for 20 to 30 minutes, and which have been prepared from a material containing two or more ethylenically unsaturated moieties and a material which contains one or more primary and/or secondary amino groups has been unknown, heretofore.